Electric telephone-transmitter



I (No Model.) 2 Sheets-Sheet 1 E J. A. MALONEY.

ELECTRIC TELEPHONE TRANSMITTER. No. 274,353. Patented Mar. 20, 1883.

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. J. A. MALONEY.

ELECTRIC TELEPHONE TRANSMITTER. No. 274,353. Patented Mar.20, 1883.

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PATENT JAMES A. MALONEY, OF WASHINGTON, DISTRICT OF COLUMBIA, ASSIGNOR TO S. H. GARNEY, TRUSTEE, OF NEW YORK.

ELECTRIC TELEPHONE-TRANSMITTER.

SPECIFICATION forming part of Letters Patent No. 274,353, dated March 20, 1883.

Application filed December 19, 1882. (No model.)

To all whom it may concern Be it known that I, JAMES A. MALONEY, of-

Washington city, in the District of Columbia, have invented certain new and useful Improvements in Electric Telephone-Transmitters, of which the following is a specification.

My improvement is mainly characterized by the employment in a telephonic circuit of a condenser, which is brought into action by the vibration of the transmitter-diaphragm in such manner that when the transmitter (whichis in the line-circuit) is in use the condenser will discharge intermittently to line, with the effect of throwing onto the line a series of electrical impulses, which are transmitted to the receiving end. For the purpose of charging the condenser Iplace it in a local or charging circuit with the battery or source of electrical energy, which circuitis also completed through the transmitter; and for the purpose of en abling these two circuits to be completed through the transmitter I make use ot'a special form of transmitter, which will be presently described.

The nature of my improvements and the manner in which the same are or may be carried into client can best be explained and understood by reference to the accompanying drawings, in which I have represented the form of apparatus which I now prefer to employ.

Figure 1 is a vertical central section from front to rear of the transmitter. In this figure I have indicateddiagrammatically the circuit connections of the transmitter, which are'represented in a more elaborate way in the twostation arrangement shown in Fig. 4. Fig. 2 is a section on line .70 :r, Fig. 1, the front contact-point, together with the corresponding point on the front of the diaphragm, being removed. Fig. 3 is a front elevation of the transmitter. Fig. 4 is a diagrammatic representation of the apparatus and circuit-connections which I employ. Fig. 5 is a sectional representation of the transmitter, similar to Fig. 1, and placed upon the same sheet with Fig. 4, in order that the circuit connections through the transmitter may be more conveniently traced in connection with the circuits shown in Fig. 4.

I shall first describe the transmitter, and will then explain the circuits and the working of the apparatus placed therein.

The transmitter consists of three essential parts: .a diaphragm and two contact-points placed on opposite sides of said diaphragm, and adapted to make electrical connection with corresponding contacts on the diaphragm.

.The two contact-points are adjustable springcontrolled contact'points, and are so adjusted that normally the contact -point which completes what may be termed the charging-circult to the condenser has full contact with the diaphragm, while the other contact-point, which completes the circuit from the condenser to line, has only partial or incomplete contact with the diaphragm. The diaphragm is a part of both circuits, and, according as it has full contact with one or the other of the contact-points, it serves to permit the battery to charge the condenser or the condenser to discharge to line.

The preferred construction of the transmitter is shown in Figs. 1, 2, 3. It consists of a wooden box, A,within which isa vertical thin wooden partition, a, having an opening, I), in it, which is covered by a diaphragm, B, consisting of a thin sheet of metal applied to the front of the partition and secured thereto at its upper edge. The diaphragm is provided on its opposite faces with carbon tips or 30 points a d. Opposite to c is the carbon point 0, which is carried by an arm, 0 of spring metal, which is pressed toward the diaphragm by an adjusting-screw, 0 In like manner the other contact-point, d, is carried by 8 a spring-metal arm, (1 which is pressed toward the diaphragm by an adjusting-screw, 61 The rear of the box A is provided with a door, A, through which access can be had to the adjusting -screw (7 in rear of the dia-, phragm, and the box is provided with a hinged front door or false front, A (through which and the front wall of the box behind is formed the voice-opening A by opening which access can be had to the front adjusting-screw, 5 0 whose head projects outwardly into a re cess indicated by dotted lines at e, Fig. 1, formed in the front wall of the box. After the adjustments are effected both doors A A should be closed and locked. 10o

Upon the box A are three binding-posts. The center one, B, is in electrical connection with'the diaphragm. The post 0 is connected electrically to the front carbon point, 0, as indicated in Fig. 3, and the post D is electrically connected to the rear carbon point, d, as indicated in Fig. 2.

With a transmitter organized on this general plan I combine a battery, condenser, and telephone-receiver, the circuit-connections bei n g such that both the circuit through which the battery charges the condenser and the circuit through which the condenser discharges to line are completed through the transmitter, as shown diagrammatically in Fig. 1. In this figure battery E, having one pole grounded, is in circuit with the condenser F through wire 1, binding post 0, front contactpoints, 0 c, diaphragm B, post B, and wire 2, and the condenser discharges to line through wire 2, post B, diaphragm- B, rear contactpoints, dd, binding-post D, and line-wire 3.

Fig. 4 represents diagrammatically two stations connected in accordance with my system. Each contains a transmitter, A, a battery, E, a condenser, F, and a receiver, G.

The circuit-connections are as follows Tracing first what may be termed the chargingeircuit, which is the local circuit at each station through which the condenser is charged from the battery, one pole of battery E is grounded. The other pole is'connected by conductor 1 to front binding-post, U. Thence the circuit is made through c c, B B, condnctor 2, and condenser F, to ground. The

points 0 c are so adjusted that normally they have full and complete contact, and through the circuit thus completed the condenser is charged from the battery.

The line-circuit may be traced as follows, starting from the lelt-hand station: One pole of the condenser is grounded from the other pole, through conductor 2, to post B, thence through E, (1 ti, and D to line 3, and the receiverat theother (right-hand) station, theline at this station being connected to binding'post D, the circuit thence being completed through d d B c c U 1, through battery E, to ground.

The user speaks into the transmitter in the usual way. The diaphragm B is thereby caused to vibrate. The normal adjustment of parts is such, as hereinbefore stated, that the carbons c 0 have full contact, while the carbone (1 d have only partial contact. When,

however, the diaphragm is in vibration, it necessarily'makes complete and full contact with one and the other alternately, with the result of alternately charging the condenser from the battery and discharging the condenser to line, there thus being a series of electrical impulses transmittedover the line-wire, with the result of reproducing the voiceloudly and distinctly in the receiver at the receiving-station. I have indicated in the figure the manner in which the ordinary magneto-electrical call can be used in this system.

.H are ordinary-call-boxes'.

I are the usual angle-lever switches, provided with hooks upon which the receivers are hung, and which, by the weight of the receivers, are caused to swing in a direction to close the circuit between the call-boxes and to break the circuit between the transmitters.

Each box has one pole grounded, and the other pole provided with aconductor, with which the switch I can electrically connect.

In lieu of using a ma gneto electric call, I can use an ordinary battery-call, in which case the caltboxes would be connected to the batteries, as indicated by dotted lines-4.. Under these circumstances the call-box grounds would of course be dispensed with.

Having described my improvements, What I claim as new and of my invention is-- 1. In a telephone-circuit, the combination, with the receiver and the transmitter, of a condenser arranged and operating to intermittently discharge to line through the diaphragm of the transmitter when the latter is in use, substantially as hereinhefore set forth.

2. The combination of the transmitter, re-

ceiver, battery, condenser, and circuit-connections, substantially as described, whereby both the circuit through. which the battery charges the condenser and the circuit through which the condenser discharges to line are completed through the transmitter. t 3. The combination,with the box A and the front contact-point, mounted on an arm secured to the box, of the adjusting-screw for said contact-point, arranged so that its head will extend into a recess formed externally in the permanent frontwall of the box, and a door placed upon the outside of the front and'arranged to cover said recess, substantially as, and for the purposes set forth.

In testimony whereof I have hereunto set my hand this 19th day of December, 1882.

JAMES A. MALONEY. Witnesses:

J. WALTER BLAruqroaip, EWELL A. DICK. 

